40 PHYSIOGRAPHIC GEOLOGY. 



Fuegia may be called the axis of the ocean. This axial line is nearly half 

 the circumference of the globe in length, and the transverse diameter of the 

 ocean full one fourth the circumference : so that the facts relating to the 

 Pacific chains must have universal importance. 



The North xitlantic Ocean trends to the northeast — or at right angles, 

 nearly, to the Pacific ; this being the course of the coasts, and therefore of 

 the channel. Moreover, it is the course of the central plateau along the 

 bottom of the north Atlantic. 



The Asiatic coast of the Pacific has the direction of the northeasterly 

 system. The course is not nearly a straight line, like the corresponding 

 eastern coast of North America, but consists of a series of curves, which 

 series is repeated in the island chains off the coast and in the mountains of 

 the country back. Moreover, the curves meet one another nearly at right 

 angles. The first one, that of the Aleutian Islands, extends as a great 

 festoon between the two continents, America and Asia. The last one, which 

 is 1800 miles long, commences in Formosa, and extends along by Luzon, 

 Palawan, and western Borneo {ha, Fig. 25) to Sumatra, and terminates at 

 right angles with Sumatra; and another furcation of it {dc) passes by 

 eastern Borneo or Celebes, and terminates at right angles with Java and the 

 islands just east. The rectangularity of the intersections is thus preserved; 

 and the curve of the Australasian chain has in this way apparently deter- 

 mined the triangular form of Borneo. 



The Aleutian Islands (range No. 1) has a length of 1000 miles. The Kamchatka range 

 (No. 2) commences at right angles with the termination of the Aleutian, and bends around 

 till it strikes Japan at a right angle. The Japan range (No. 3) commences north in Sa- 

 ghalien, and curves around to Corea. The Loochoo range (No. 4) leaves Japan at a right 

 angle, and curves around to Formosa. The Formosa range (No. 5) is explained above. 

 There is apparently a repetition of the Formosa system in the Ladrones near lon- 

 gitude 145° E. 



(3) East and West Indies. — The general courses in the East Indies have 

 been mentioned on pages 38, 39. In the West Indies and Central America 

 there is a repetition of the curves of the East Indies. The course of the 

 range along Central America corresponds to Sumatra and Java ; and the line 

 of Florida and the islands to the southeast makes another range in the 

 same system. 



(4) The American continents. — In Novth. America, the northwest system 

 is seen in the general course of the Eocky Mountains, the Cascade Range, 

 and Sierra Nevada ; in Florida ; in the line of lakes, from Lake Superior to 

 the mouth of the Mackenzie ; in the southwest coast of Hudson Bay ; in 

 the shores of Davis Straits and Baffin Bay ; — and with no greater divergen- 

 cies from a common course than occur in the Pacific. The northeast system 

 is exemplified in the Atlantic coast from Newfoundland to Florida, and, still 

 farther to the northeast, along the coast of G-reenland ; and to the south- 

 west, along Yucatan, in Central America. The Appalachian Mountains, the 

 river St. Lawrence to Lake Erie, and the northwest shore of Lake Superior, 

 repeat this trend. 



